Possibilities for inducing drought tolerance in wheat using gamma rays

Drought is a limiting factor in the production of wheat in arid and semi-arid regions. Programme for improving this crop through mutations are taking place in many countries. Therefore, the present research was carried out to reveal the possibilities for inducing drought resistance in a local bread wheat cultivar (Giza-157) using gamma rays. The seed lots of this cultivar were irradiated with 0 (control), 75, 100 and 125 Gy of 60Co gamma rays and planted to produce M1 seed. In the following seasons, this process was repeated on fresh seed and the off-spring of M1 and M2 in such a way as to ensure the planting of the M1, M2 and M3 generations in one field experiment. To study the effect of drought, the second and fourth irrigations in the drought stressed treatment were withheld. The normal irrigation treatment consisted of four irrigations between planting and harvesting. The results showed that under drought stress irrigation conditions (especially at 125 Gy) significant earliness occurred in the M2 and M3 generations, which could be encouraging for inducing better drought tolerance. The mean weight of seed yield/plant increased at 100 and 200 Gy (M2) and at 100 Gy (M3) under drought conditions. The latter treatment produced the highest seed yield, i.e. better drought tolerance. It is concluded that inducing drought resistance in some cultivars of bread wheat using different doses of gamma ray can be recommended as a goal for inducing earliness, which could lead to a relatively good yield under drought conditions. 4 refs, 1 tab